US2128388A - Refrigerating apparatus - Google Patents

Description

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Aug. 30,. 1938. H. M. WILLIAMS r AL 2,128,338

'REFRIGERATING APPARATUS Filed Dec. 31, 1934 p a: 2% I O xv: lid 1 m 7 as 66 :7; m nn INVENTORS.

#144) M Wan/m: A luurJ. 77 mm.

HIE/k ATTORNEYS.

Patented Aug. 30, 1938 NlTED STATES;

OFF-ICE aizaass anrnrcanarmc Amrros Application December 31, 1934, Serial No. 759,812

4 Claims.

This invention relates to refrigerating systems and particularly to the means employed in such systems for causing circulation of refrigerant therein.

An object of the present invention is to prevent absorption of refrigerant in a closed volatile refrigerating system by oil employed to lubricate moving parts of the refrigerant circulating element or compressor of the system through which the refrigerant is circulated.

Another object of the invention is to provide a refrigerating system with a refrigerant circulating element or compressor which has a substantially dry crankcase compartment as distinguished from conventional refrigerating systems wherein a body of lubricant is ordinarily contained in the crankcase of the compressor thereof.

In carrying out the foregoing objects it is a still further object of the invention to force a lubricant, such, for example, as oil, through or between the bearing surfaces of operating parts of a compressor of a refrigerating system, to drain the lubricant circulated to the compressor parts from the compressor, and to isolate thev lubricant removed from the compressor from refrigerant in the refrigerating system.

Further objects and advantages of the present invention will be apparent from the following 0 description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing: Fig. 1 discloses a refrigerating system shown diagrammatically and having my invention embodied in the refrigerant circulating element thereof which element is shown on an enlarged scae partly in section and partly in elevation; an m Fig. 2 is a sectional view through the oil pump employed in the present invention and is taken on the line 2-2 of Fig. 1.

Referring in detail to the drawing there is shown for the'purpose of illustrating the invention a compressor-condenser-expander type of refrigerating system employing an expansion valve for "admitting refrigerant to the evaporator of the system and a thermostat responsive to temperatures of the evaporator for actuating a switch for intermittently or cyclically starting and stopping operations of the system. However, the invention is equally applicable to a so-called flooded type refrigerating system in which a float valve controls the entrance to the evaporator and in which operation of the system is controlled 55 by a switch responsive to pressures in the system. My invention may be of more importance when applied to the latter type of a refrigerating system due to the relatively large amount of refrigerant in such system and which refrigerant is ordinarily circulated in absorbing contact with 5 the lubricant contained therein.

The system disclosed in the drawing comprises a refrigerant circulating element, pump or compressor l0 operated by an electric motor I I. The compressor or pump it forces refrigerant such 10 as difluorodichloro methane (CClzFzL. or any other suitable refrigerant through a suitable check valve, which is ordinarily contained in the top portion or head i2 of the compressor, and thence through conduit or pipe l3 into a con- 15 denser it. The compressed refrigerant is condensed and liquefied in condenser l4 and collects in the receiver it. From the receiver l6 the liquefled refrigerant passes by conduit i'l through an expansion valve is and into the cooling coils 20 or evaporator IQ of a refrigerating element where it performs its refrigerating effect in the wellknown manner. From the cooling coil 19 the vaporized refrigerant passes by means of the pipe 2! back to the refrigerant circulating element, 25 pump or compressor Ill. The thermostatic device is represented by the numeral 22 and is disposed so as to be responsive to the temperature of the cooling coil is or may be responsive to the temperature of the space beingrefrigerated by this coil. This device is used to actuate, as by means of a diaphragm, bellows or the like 23, a circuitmaking and breaking switch 24. This switch is shown in its motor non-operating position by the full lines and contacts 25 and 26 and in its opera- 3r tive position'by the dotted line. After the system is put in operation and the compressor It has been idle for a short period of time, pressure within the evaporator l9, pipe 2|, and the compressor crankcase 28 is relatively high. During this idle period the temperature of 40 a fluid in bulb 22 rises and increases its own vapor pressure and this pressure acting inside the flexible diaphragm or bellows 23 will expand same and thus force the switch 24 and its contacts 25 and 26 into circuit-making position to causeoperation of the motor ll employed for driving the refrigerant circulating element, pump or compressor it. After the compressor has operated for a short period, say for a few minutes, the temperature and the environment of bulb 22 is reduced, and the fluid pressure therein is reduced sufllciently to permit the diaphragm or bellows 23 to be contracted, thus actuating the switch contacts 25 and28 into openposition for breaking the electric circuit to the motor H.

the connecting rod 33 reciprocates a piston 34 se- Operations of the system continue as described as long as such system is connected with the source of power. The compressor, or pump l0 may be of any suitable form and may include an eccentric 3| within the crankcase 28 which eccentric is secured to the rotating shaft 32 and has a connecting rod 33 actuated thereby. Movement of cured to the upper end thereof. This piston 34 has located therein any suitable or conventional check valve (not shown) which opens upon the down stroke of the piston to permit the entrance of refrigerant gas into the cylinder 36 above the piston but seats or remains closed during the up or compression stroke thereof.

' The crankcase 28 of the compressor, or pump it) is on the low side" of the system. While the compressor is operating, the refrigerant pressure therein is relatively low, but during the idle period this pressure gradually rises because of the rise of temperature of'the liquid refrigerant in the low side of the system. During this idle period, therefore, the refrigerant absorbing power of lubricant ordinarily contained as a body thereof in the crankcase of conventional compressors increases and a quantity of refrigerant is absorbed, depending, of course, on the natural afiinity between the two fluids, the temperature of the lubricant and the pressures of the fluids. The volume of the lubricant in conventional compressor crankcases (which is a mixture of oil and refrigerant with a major portion of oil) therefore tends to increase due to this absorption of refrigerant during the idle periods of the system. This is particularly true where the refrigerant and lubricant are miscible in all proportions, but the same problem exists, in varying degrees, even when they are only partially miscible. A body-of oil as contained in the crankcase of conventional compressors is thereby readily diluted thus decreasing the lubricating properties thereof.

In a conventional apparatus not provided with my invention, the lubricant level would tend to rise to a detrimentally high level during the idle period of the system. This rise in the level would occur because of the absorption of the refrigerant by the lubricant as described above. With such a detrimentally high oil level a violent boilmg or foaming would occur when the compressor starts due to the release of gaseous refrigerant from the lubricant by the quick reduction in pressure. Under such conditions large amounts of liquid are likely to pass through the valve, not shown, but located in the piston 34 into the compression chamber 36 above the piston with undesirable results such as causing stalling of the'motor II and burning or blowing of fuses in the power circuit. A great amount of oil is also circulated by the pump or compressor with refrigerant to other elements of the refrigerating system and this is likely to cause the compressor to operate without being properly lubricated.

According to this invention, however, the problems encountered in the use of ,conventional compressors are eliminated. To this end there is provided an apparatus wherein the pump or compressor crankcase 28 is maintained in a substan- :tially dry condition or in other words, is devoid of a body of lubricant therein while at the same time providing positive and efficient lubrication of moving parts of the pump or compressor i0. Referring again to the drawings it will be noted that the compressor, or pump l0 disclosed therein has its operating shaft 32, which is rotated by operation of the motor H, extending to a point adjacent a counter-bored opening or chamber 40 provided on one side of the compressor crankcase 28. A unitary pump, preferably although not necessarily, of the vane type, the construction and operation of which pump is well-known to those skilled in the art, is adapted to be located within the chamber 40. The pump includes a rotor 4| having two vane members 42 and 43 located in a slot provided therefor'in' the rotor and which vanes are forced outwardly away from one another by a spring 44. A ring member 45 is stationarily clamped, by screws 46, between an end plate 41 and another end plate 48 which said another end plate is stationarily clamped tothe wall of chamber 40 by a plurality of bolts or screws 49. The ring 45 is mounted concentrically with respect to chamber 40 and compressor shaft 32 and is provided with an eccentric opening which serves as a cylinder in which the rotor 4| rotates. In order to cause rotation of rotor 4| within the eccentric cylinder provided by ring 45 the rotor is provided with shaft portions 5i and 52 formed integrally with and extending outwardly from each side of the rotor. The shaft portion 5| of rotor 4| is journaled in an opening provided therefor in the end or sealing plate 88. The other shaft portion 52 of rotor 6! has its end squared as at ,53 so as to be received in a similarly shaped groove or slot 54 provided in the end of the compressor shaft 32. (See Fig. 2.) The connection of shaft'portion 52 with the compressor shaft 32 obviously causes operation of the pump just described when the compressor to is operated by motor ii. During rotation of the rotor 4| a suction is created on one side of the annular edge of the rotor between the vanes 62 and 43 and at the same time a pressure is created on the other side of rotor 4| between the vanes 42 and 43 as is well-known to those familiar with pumps of the type disclosed. Therefore I provide suitable outlet openings 55 in the uppermost portion of ring 45 on the pressure side of the pump and also a similar inlet opening 56 (see Fig. 1) on the suction side of the pump. The

' lar to the outlet openings'55 is, of course, blocked off or prevented by end plate 41 from communicating with the pressure chamber 40 but this inlet opening 56 is in open communication with an inlet port or conduit connection 6|. A speciflc type of pump having been briefly described,

it will be understood, however, that any suitable or conventional pump may be employed to carry .out the objects of the present invention.

A closed fluid circuit is' connected to the pump above described and is adapted to contain, in one portion thereof, a quantity of oil to be circulated to or through the bearing surfaces of moving parts of the compressor ID for lubricating such parts. A conduit 65 is adapted to have its one end connected, by any suitable connecting means, with the outlet port or connection 58 of the pump and the other end of conduit 65 is adapted to be connected to a connection 66 in the housing 61 of a valve device generally designated by the reference character 68. The valve device 63 has a pipe connection 69 with the lowermost The inlet portion of the interior of the crankcase 28 of com- 7 pressor I 8 and is also connected, by the flange couplingi'll and copuler 12, with a tank 13. A conduit 14 is adapted to have its oneend 15 connected, by any suitable connecting means, with the bottom of tank 13 and the other end 16 of conduit 14 is adapted to be connected with the inlet connection 6| of the oil pump secured to and operated by the compressor I0. The valve de- 7 vice 68 included in the closed fluid pressure circult just described includes a plunger 3| having a valve 82 attached thereto or formed on the lower end thereof and which valve is adapted to 3 open or close the passage 33, leading from concloses the conduit or passage by the opening 36 is for the purpose of equalizing -the pressure on each side of the plunger 3| and for permitting its free movement when pressure is applied to chamber 31 beneath the shouldered portion 84 thereof. A spring 88 normally tends to force plunger 33 extending from the compressor crankcase to the tank 13 when the pump attached to the compressor is idle.

The chamber 48 of the oil pump is in open communication with the outlet connection 58 thereof and'is also in open communication with a passage 9| provided in the center of the operating shaft 32 of the compressor |0.- The passage 9| in the shaft 32] communicates with any desired number of grooves, passages, etc., provided in other operating parts ofthe compressor which are attached or connected to the shaft 32 and are to be lubricated by oil circulated by the oil pump. For example, the passage 9| may communicate with a hole extending to the surface of the shaft 32 and communicating with a feeding groove or the like provided in the eccentric 3| which leads to the-groove 92 in the connecting rod 33. The groove 92 communicates with an opening or hole 93, in the connecting rod 33, which extends to an opening 94 provided in the wrist-pin 95 for permitting the connection or bearing surfaces of the lubricated. The method of grooving and providing the oil feeding holes in shaft 32 and the other operating parts of the compressor I8 is well-known to those skilled in the art of providing forced lubrication to operating parts of engines,

compressors, etc.

Substantially all of the oil employed in the apparatus disclosed for lubricating the moving parts of the compressor tank 13 of the closed oil circuit comprising the compressor l0, conduits 36, valve device 33, conduit 14 and the oil pump. When the refrigerating system is put into operation to cause intermittent or cyclical operations of compressor ID, for withdrawing evaporated or gasified refrigerant from the evaporator l8 and for circulating the compressed refrigerant to the condenser l4, the oil pump connected with the compressor or pump shaft is also operated. Operation of. the oil pump sucks or" draws oil through the inlet opening 36 and conduit "from the reservoir thereof in tank I3 and forces this oil through the outlet openings 53,,notch or slot 31, and through slot or groove 33 to chamber 43. Since the outlet 81, which receives the 8| downwardly so that valve 82 inclined bottom wall of the crankcase .23 and flows therefrom, through the pipe 39 and passage 8 and piston 34 to be I8 is contained in theconnection 53 is also in open communication, by

way of the slot 51, with the openings 55 oil is also forced, by .pres'sure created by the pump, to the.

' pin 95 thereby lubricating the bearing surface of operating parts of the compressor. As before stated oil under pressure is circulated to conduit 65 simultaneously, with the circulation thereof to the bearing surfaces of the various parts of compressor Ill. The pressure created by the oil pump or the oil flowing to conduit 65 is forced through the conduit connection 63, in the valve device 68, into the bottom of chamber 31 below the enlarged portion of plunger 8| provided by the shoulder 84 formed thereon. The pressure of the oil pump or the oil beneath the plunger 8| causes the plunger to move or to be actuated uppump during operation of the compressor Ill maintains the plunger 3| in its uppermost position and thereby maintains valve 82 in its open position as long as the compressor is operating;

from the bearing surfaces l8 drips to the Therefore oil flowing of moving parts of compressor 83, to the interior of tank 13.- The compressor crankcase 28 is therebymaintained in a substan- 'rially dry condition or in other words; is free of a body of oil and thus the oil does not accumulate therein. When the compressor stops the pressure throughout the closed 011 circulating system equalizes and the plunger 3| in the valve device 38 is moved by spring 88 to its lowermost position to close valve 32 to cut off communication between the compressor crankcase 23 and the oil reservoir in tank 13. The oil employed for lubricating the moving parts of compressor-l3 and which flows from these parts to the trap 1.3 during cpcration of the compressor is thereby isolated or. maintained out of contact with the refrigerant employed in the refrigerating system.- In case some oil is carried through the compressor l8 during the running period thereof it eventually finds its way back to the compressorcrankcase 23 and to the oil circulating circuit after passing through the condenser and evaporator with the refrigerant in the refrigerating system.

Thus it is apparent that there is provided an improved refrigerating system which will not be rendered inoperative by the absorption of refrigerant of the system by a bodyof lubricant; in the compressor. There is provided a refrigerating apparatus in which the lubricant and re-' frigerant employed therein are miscible or partially miscible and in which the miscibility or ixing thereof is prevented so as to eliminate t e difficulties of hard starting, etc;, of the compressor which, occurs in conventional refrigerant pumps or compressors. The invention therefore prevents the refrigerant of the refrigerating system from diluting the lubricating-oil and consequently proper and efficient lubrication of the operating parts of the compressor is insured. The

wardly to thereby lift valve 32 and open the pasa stantially dry crankcase and oil will not be circulated from the compressor to other elements of the refrigerating system, thus problems, inherently present in conventional refrigerating systems, of returning oil from certain elements of. the refrigerating system to the compressor crankcase are eliminated.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form,

it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In combination with a compressor employed to circulate a refrigerant through a refrigerating system in which the refrigerant is miscible with a lubricant contained in the system, means for circulating the lubricant to operating parts of the compressor, said means being rendered eifective by operation of the compressor for circulating the lubricant to operating parts thereof, means for conductingthe circulated lubricant away from said compressor, means connected with said conducting means for receiving lubricant conveyed from said compressor, said lubricant receiving means also having. a connection with said lubricant circulating means for supplying it with lubricant to be circulated, means rendered effective' upon stopping the-operation of said compressor for closing'said' conducting means to isolate the lubricantqremoved from said compressor from refrigerant in the refrigerating system, and said last named means also being rendered effective automatically in response to operation of said compressor for opening said conducting means.

2. In combination with a pump employed to circulate arefrigerant through a refrigerating systemin which the refrigerant is miscible with a "lubricant contained in the system, a second pump for circulating the lubricant to operating parts of said first named pump, said second named pump being rendered effective simultaneously with operation of said first named pump, means for conducting the circulated lubricant away from said first named pump, means connected with said conducting means for receiving lubricant conveyed from said first named pump, said lubricant receiving means also having a connection with said lubricant pump 'for supplying it with lubricant to be circulated, means rendered effective upon stopping the operation of one of said pumps for closing said conducting means to isolate the lubricant removed from said first named pump from refrigerant in the refrigerating system, and said last named means also being aieasee rendered effective automatically in response to operation of one of said pumps for opening said conducting means.

3. In combination with a compressor employed to circulate a refrigerant through a refrigerating system in which the refrigerant is miscible with a lubricant contained in the system, said compressor having a substantially dry crankcase through which refrigerant flows during circulation thereof through the system, a pump connected to and operated by said compressor for circulating the lubricant to operating parts of the compressor, conduit means for conducting lubricant from operating parts of the compressor and for preventing accumulation of lubricant in the compressor crankcase, a reservoir connected with said conduit means for receiving lubricant conveyed from said compressor for supplying it with lubricant to be circulated, said lubricant reservoir having a connection with said pump, a valve for controlling the flow of lubricant through said conduit means, said valve being actuated automatically to open said conduit means by pressure created by operation of said pump, and said valve being actuated automatically upon stopping the operation of said pump to close said conduit means for isolating lubricant removed from said compressor from refrigerant in the refrigerating system.

4. In combination with a compressor employed i0 circulate a refrigerant through a refrigerating system in which the refrigerant is miscible with a lubricant contained in the system, a pump for circulating the lubricant to operating parts of the compressor, said pump being operated simultaneously with operation of said compressor, conduit means for conducting lubricant away from said compressor, a reservoir connected with said conduit means for receiving lubricant conveyed from said compressor, said lubricant reservoir having a connection with said pump for supplying it with lubricant to be circulated, a spring pressed valve for controlling the flow of lubricant through said conduit means, means communicating with said pump and with said valve whereby pressure created by said pump overcomes the force exerted by said valve spring, said valve being actuated automatically to open said conduit meansupon operation of said pump, and said valve being actuated automatically upon stopping the operation of said pump to close said conduit means for isolating lubricant removed from said compressor from refrigerant in the refrigerating system.

' HARRY M. ALBERT J. TIMMER.

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